"The aim is to create awareness of museums, so that, when they are under threat, there will be public outrage. They mustn't be taken for granted. At the moment we're doing this through Museums Week, which is now becoming an institution - as someone once told me, in Britain if you do something once it's a novelty, if you do it twice it's an institution."
Although the Campaign for Museums has no budget of its own, it is strongly supported by a variety of associations. "It's entirely voluntary," says Grossman, "an SAS-type operation. We just want to go in and hit where we're needed with the minimum of grandeur or bureaucracy."
Lobbying people and begging for money take up around half his working hours at present. Why does he do it? The answer lies in Grossman's Massachusetts childhood. "I was very lucky to grow up near a couple of wonderful museums: the Peabody at Salem, which is one of the greatest maritime museums, and the Museum of Fine Arts in Boston, which is just the most wonderful museum in the world. Fortunately, my father did a lot of business with the Museum of Fine Arts, so as a child I usually went to a museum once a week. It was just as everyday a part of my life as going out to play baseball or going to the beach. But it was always thrilling. Even now, when I go back to the Peabody Museum, I still get the same thrill and I still remember what it felt like as a very, very small child. The Peabody has a great collection of ship models, plus Hawaiian chiefs' capes and spears from the South Seas, all of which was enthralling. I was very lucky to have such an outstanding museum right on the doorstep."
To hear what's happening in museums on your doorsetep this month, phone your local museum or read on.
Not even open yet, the embryo Museum of Soho is staging children's walks on the two Saturdays of Museums Week. Parents can come, too, say the organisers, "providing they promise not to dampen the atmosphere". There will be two types of walks to cater for both children who already know the area and those who don't (booking: 0171-439 4303). "We'll take a sensible line on the brothels and strip clubs," says a spokeswoman. "Local children are immune to them anyway." Fund-raising is now gearing up towards the museum's hoped-for opening in five years' time, when it will house displays showing the social history of Soho over 400 years.
Who needs Hawaiian chiefs' capes when, on Thursday 23 May, you can attend workshops on how to produce your own hand-made bricks at Louth Museum (4 Broadbank, Louth, Lincolnshire LN11, 01507 601211)? "Anyone prepared to roll up their sleeves and put on a plastic pinny is welcome between 2 and 4pm," says curator Jean Howard.
You can help roll out Victorian-style pastry at the Lloyd George Museum (Llanystumdwym, Criccieth, Gwynedd, 01766 522071; 16, 20, 22, 23 May) during Victorian cookery demonstrations in the former Liberal PM's boyhood home. There are also daily lessons (not Suns 19, 26 May) in the Victorian schoolroom, and shoemaking demonstrations from 20 to 24 May in the workshop of Lloyd George's shoemaker uncle.
A recreation of the sights and sounds of WW1 is being staged at Fort Nelson (Down End Rd, Fareham, Hampshire, 01329 233734, 26-27 May), the Royal Armouries' artillery museum near Portsmouth and home of pieces of the Iraqi supergun impounded in 1990. This Sunday, Ubique Troop, the WW2 living history display and gun team, will fire the Fort's 25-pounder field guns and 5.5 gun howitzer. Stand clear.
BEST OF THE REST: COUNTRYWIDE EVENTS 18-26 MAY
Rare opportunity for punters to get their hands on the fossil bones of small animals found in Cresswell caves. Visitors can help extract the skeletons of ice-age voles and mice and examine them under the microscope.
Worksop, Notts (01909 720378) Sun 19 1-4pm, behind-the-scenes tours running all week, pounds 1
Fantastic range of hands-on events for children includes traditional baking, wool spinning, owl conservation, Punch and Judy, toy-making demonstrations, pyrography (working with a hot rod to make an iron badge), origami, storytelling, demonstrations of how to make and play Northumbrian pipes, lace-making, brass rubbing, marbling and printing.
Burton Rd, Lincoln LN1 (01522 528448) Sat 18 10am-12.30pm, 1.30-4pm, pounds 1.20, 60p children
A selection of traditional music from the Royal Courts of Central Java. There will also be workshops for beginners.
Durham (0191-374 7911) Sun 19 3-4pm
Chemicals For Life, a state-of-the-art interactive gallery with over 50 displays brings the period table to life. Exhibits include a talking chemical plant and The Game of Health, where visitors are challenged to travel from past to present without falling ill from a deadly disease.
Widnes, Cheshire (0151-420 1121) Tue-Sun 10am-5pm, pounds 3.95, pounds 2.95 children
Museum conservationists work behind the scenes preserving the 1.2m artefacts in this collection which range from tiny beetles to Old Masters, from Egyptian mummies to Cromwell's boots. This tour allows visitors to handle objects, find out what is wrong with them and guess what treatment they need.
William Brown St, Liverpool L3 (0151-478 4399) Sat 18 12.30pm, 1.45pm, 3pm
An archaeological guided walk that traces a trail through the city's kirks, taking in St Giles, Magdalen Chapel, Lady Yester's Kirk and Canongate Kirk. The tour links architecture and excavated evidence to illustrate the history of religion since the time of David I.
Archeology Section (0131-558 1040) Thur 23, meet at Castle Esplanade, booking essential
A week of theatre, dance, opera, music and puppetry. The Museums and Galleries of Edinburgh have planned myriad designing and making activities, art work and dressing-up - all with a pirate theme.
Inverleith Park (0131-553 7700) Mon 20-Mon 27, festival day pass pounds 2, booked sessions Tue-Fri, drop in all day Mon 20, Sat 26, Sun 27
Canon Michael Butler will lead the traditional blessing of the nets. Free entertainment for families includes a children's play bus, bands and buskers. Fishing boats will anchor offshore and their fresh catches will be barbequed.
201 Kings Rd (01273 723064) Sun 19 11.30am-6pm
Discover and explore the world of mechanical movement. Exhibits include wind-powered inflatable sculptures and self-propelling potato-mobiles. Also a model of a fire-eating man and an enormous mechanical bird with an 11ft wingspan.
Surrey (01932 565764) to 4 Jun 12.30-4.30pm
The Renaissance anatomist stars in a new music theatre work about human dissection. Two opera singers and an actor perform the roles of celebrant and cantors (above).
London SE1 (0171-955 4791) Tue 21-Sat 1 Jun 8pm
Brave visitors can get to grips with birds of prey such as the Bengal Eagle Owl and handle polecat ferrets (left). Wildlife experts will be on hand to explain the animals' habitat.
Tewkesbury, Glos (01684 297174) Sat 18
Meet the experts who conserve the 600,000-year-old bones of the West Runton Elephant.
East Dererham, Norfolk (01362 860563) Thur 23 10am, guided tours every half hour
Children can find hidden objects and complete quizzes around the museum. Throughout the week there will also be a range of hands on events and demonstrations which look at local crafts such as slate carving and peg doll making.
Gwynedd (01248 353368) Sat 18-Sun 26 10am
The only operational wrought iron works in the world throws opens its furnaces. Costumed demonstrators will be working the hot metal.
Telford, Shropshire (01952 433522) Sat 18-Sun 19, pounds 8.95, pounds 5.30 children, under-6s free
YORKSHIRE & HUMBERSIDE
Local musicians play music appropriate to the periods of painting on display.
York (01904 551861) Sat 18-Sun 26 10am-5pm
Cashing in on Museums Week, the Yorkshire Museum will present a Coin Roadshow starring Grunal Moneta and his travelling mint.
York (01904 629745) 10am-5pm, pounds 3, pounds 2 children
q Museums Week leaflet available from Tourist Information Centres around the country